A novel thionation protocol for amide compounds, with the system rhodanine/secondary amine has been discovered. Clean and efficient synthesis of a variety of thioamides can be achieved through this simple and convenient method using MCM-41 mesoporous silica as an acid catalyst. For this purpose we have synthesized MCM-41 silica and characterized by using an array of sophisticated analytical techniques like BET, HR TEM, EDX, XRD, 29Si MAS NMR and FTIR. This reaction is therefore a very neat example of a functional group interconversion. © 2013 Elsevier Ltd. All rights reserved.